Three-stage AIDS incubation period: a best case scenario using addict-needle interaction assumptions

In this paper we extend the 'needles that kill' model discussed in Kaplan & O'Keefe (1993) to allow addicts to progress through three-stages of variable infectivity prior to the onset of full-blown AIDS, and where the class of infectious needles is split into three according to the different levels of infectivity in addicts. Given the structure of this model we are required to make assumptions regarding the interaction of addicts and needles of different infectivity levels. We deliberately choose these assumptions so that our model serves as a lower bound for the prevalence of HIV under the assumption of a three-stage AIDS incubation period. We find that there is a critical threshold parameter R0 which determines the behaviour of the model. If R0 > 1 then there is a unique endemic equilibrium which is locally stable if, as is realistic, the timescale on which addicts inject is much shorter than that of the other epidemiological and demographic processes. Simulations indicate that if R0 > 1, then provided that disease is initially present in at least one addict or needle then it will tend to the endemic equilibrium. In addition, we derive conditions which guarantee this. We also find that under calibration the long-term prevalence of disease in the 'needles that kill' model is the same as in our three-stage model.

Schistosoma mansoni: use of a subtractive cloning strategy to search for RFLPs in parasite-resistant Biomphalaria glabrata

A subtractive cloning strategy has been applied for the identification of two cDNA clones whose corresponding transcripts were elevated in Schistosoma mansoni-resistant (BS-90) compared to susceptible (M-line) snails. Clone pBS11 encoded a 1.9-kb transcript that was more elevated compared to a 500-bp transcript encoded by clone pBS12. Consequently, more attention was focused on the molecular characterization of clone pBS11. Results showed that the transcript encoded by this clone was expressed in the albumen gland and was developmentally regulated. Sequence analysis of pBS11 demonstrated the presence of an open reading frame that corresponded to a novel Biomphalaria glabrata albumen gland gene product. Comparative Southern analysis of the resistant and susceptible snail lines using pBS11 as probe indicated the presence of a BamHI and EcoRI RFLP between the two strains.

Serum and gastric luminal epidermal growth factor in Helicobacter pylori-associated gastritis and peptic ulcer disease

BACKGROUND

Helicobacter pylori is the cause of chronic (type B) gastritis, duodenal ulceration (DU), and gastric ulceration (GU). Smoking is associated with delayed ulcer healing. Epidermal growth factor (EGF) is produced in the salivary and Brunner's glands of the upper gastrointestinal tract, inhibits gastric acid secretion, and is a powerful mitogen.

MATERIALS AND METHODS

We sought to determine gastric luminal EGF (GL-EGF) in smokers and patients with Hp-associated DU and the effects of Hp eradication. Our aim was to determine GL-EGF in patients with GU and the effect of ulcer healing and to measure serum EGF in patients with Hp gastritis with or without DU disease.

RESULTS

GL-EGF was reduced in smokers compared to controls (p = .008). Subjects with HP gastritis had reduced GL-EGF compared to controls (p = .0002). There was no difference in GL-EGF between Hp-positive subjects who had DU and those with chronic gastritis alone. Eradication of Hp from those patients with DU had no effect on the low levels of GL-EGF. There was no difference between GL-EGF in Hp gastritis alone and in Hp-associated active GU. GL-EGF fell after ulcer healing (p = .04), a difference confirmed by analysis of paired samples from patients before and after ulcer healing (p = .03). There was no difference in serum EGF between controls and subjects with Hp infection. There was no difference in serum EGF in subjects with DU associated and non-ulcer-associated gastritis.

CONCLUSIONS

Subjects with Hp gastritis, or those who smoke, had low concentrations of GL-EGF regardless of whether DU was present. Eradication of Hp did not return the concentrations of GL-EGF to normal in DU subjects. Individuals and Hp gastritis and inactive GU had low levels of GL-EGF compared to non-ulcer Hp infection. The relative increase in GL-EGF that occurred with ulceration of the gastric mucosa may have resulted from the development of an ulcer-associated cell lineage. Serum EGF did not play a role in the pathogenesis of Hp gastritis or of associated DU ulcer disease.

Fluorescent polymerase chain reaction of a panel of CA repeats on chromosome 6 in the indolent phase of follicular centre cell lymphoma

Twenty-four cases of histologically defined follicle centre cell (FCC) lymphoma have been examined for allele imbalance at 19 microsatellite loci spanning the length of chromosome 6, including six markers within the major histocompatibility complex (MHC), using fluorescent polymerase chain reaction (PCR) to amplify microsatellites. Nineteen cases were observed in which imbalance of one or more markers on chromosome 6 had occurred (79%). The frequency of allele imbalance was significantly higher on 6p than 6q, and two regions of deletions, 6p24-25 and 6p21.3-23, were identified in which the loci showed a significantly high allele imbalance frequency.

Antenatal screening for cystic fibrosis

OBJECTIVE

To assess the practicality of implementing antenatal screening for cystic fibrosis in Yorkshire.

DESIGN

Prospective study in which all pregnant women were offered testing for the delta F508 mutation which accounts for about 85% of carriers in Yorkshire. The reproductive partners of those found to be cystic fibrosis carriers were then tested and any carrier referred for genetic counselling.

SETTING

Antenatal clinics in two hospitals and eight general practices.

POPULATION

Six thousand and seventy-one pregnant women.

RESULTS

A total of 3773 women (62%) accepted the screening offer. This was a lower uptake rate than in other published UK studies: Aberdeen (85-91%), Manchester (85%), Edinburgh (76-84%) and Oxford (67%). Nonetheless there were large and statistically significant differences in the uptake rate between centres within the study: 78% and 60% for the two hospitals and 67% for the general practices. One hundred and thirty women (3.4%) were found to be carriers and three carrier couples were identified. The median time interval for the laboratory to produce a result was five days and the cost was pounds 16 on average.

CONCLUSIONS

Antenatal screening for cystic fibrosis does not pose any special practical difficulties. It would be feasible to introduce it into routine practice in Yorkshire.

Promoter region polymorphism in the human TNF-alpha gene is not associated with lichen sclerosus

The pathogenesis of lichen sclerosus remains unknown. However, it has been frequently associated clinically with autoimmunity. The MHC haplotype A1, B8, DR3 is associated with many autoimmune conditions and has also been associated with the uncommon allele of the tumour necrosis factor (TNF-alpha) promoter polymorphism. This allele is also associated with higher production of TNF in vivo and in vitro, and thus it has been speculated that it is the TNF-alpha gene which underlies the genetic association of many diseases with the autoimmune haplotype. There have been many reports of HLA associations with lichen scleroses, but these have not been concordant. We therefore decided to analyse the TNF-alpha polymorphism in patients with lichen scleroses to determine if TNF-alpha was likely to play a role in susceptibility or severity of lichen scleroses. No association between alleles of the TNF-alpha polymorphism and lichen scleroses was found.

Allele imbalance at tumour suppressor loci during the indolent phase of follicle centre cell lymphoma

We have examined 41 cases of follicle centre cell lymphoma with fluorescent PCR of microsatellite repeats closely linked to or within six tumour suppressor gene loci (APC, DCC, P53, RB1, WT1 and NM23). These probes are highly informative with heterozygousity rates in the range of 57%-90%. In addition we have used four loci from chromosome 6 (D6S260, TNFa, D6S281 and D6S262) as control loci which are unlikely to be involved in the pathogenesis of lymphoma. Of 369 informative PCR reactions allele imbalance was identified in 38 (10%) and this was seen in 23 of the 41 cases. Looking at individual loci allele imbalance was seen in APC(1) 11%, APC(2) 12%, P53(1) 5%, P53 (2) 7%, WT1 5%, RB1 13%, DCC 18% and NM23 0%. This frequency of change was no different from that seen at the control loci D6S260 16%, TNFa 20%, D6S281 4% and D6S262 9%. In the indolent phase of germinal centre cell lymphoma there is therefore quite a high rate of allele imbalance at all loci but this is no higher in those loci linked to tumour suppressor genes.

Microsatellite instability in follicle centre cell lymphoma

Fluorescent polymerase chain reaction (PCR) was used to assay 12 microsatellite markers (APC x 2, DCC, P53 x 2, RB1, NM23, WT1, D6S260, D6S262, D6S281 and TNFa) to look for evidence of microsatellite instability in 40 cases of follicle centre cell lymphoma (FCC). Evidence of novel alleles seen in the tumour tissue but not the normal uninvolved tissue was seen in seven cases (17%). In only two of these cases (5%) was more than one locus involved but in these cases multiple affected loci were seen (4/12 and 7/12 respectively). The detection of microsatellite instability indicates a DNA repair defect such as that which would be predicted to occur in cells with mutated mismatch repair genes, a novel finding in FCC lymphoma.

Schistosoma mansoni: changes in the albumen gland of Biomphalaria glabrata snails selected for nonsusceptibility to the parasite

The LAC-line strain of the snail Biomphalaria glabrata has very low susceptibility to the parasite Schistosoma mansoni and a very low reproductive potential. Upon examination of the reproductive tract of these snails, light and electron microscopy revealed obvious abnormalities in the albumen gland. Secretory cells that are normally cuboidal in susceptible NMRI (F0) snails were squamous in LAC-line snails. These LAC-line cells contained small secretory granules and negligible rough endoplasmic reticulum and Golgi, compared to large granules and an extensive array of both organelles in F0 albumen gland cells. Comparative analyses of soluble protein extracts of F0 and LAC-line albumen glands showed several qualitative differences. Among the most prominent was an 18-kDa protein in F0 snails that was remarkably reduced in the soluble protein extracts of LAC-line snails. Also, metabolic incorporation of [35S]-methionine was impaired in LAC-line albumen glands. Whether these albumen gland changes are caused by decreased susceptibility to parasitism is yet to determined.

Some selected psychological and social characteristics of veteran psychiatric inpatients without stable housing

In this study were compared scores on selected MMPI subscales and demographic variables from 58 veterans with stable housing and 54 veterans without stable housing. Both groups were selected from the same inpatient psychiatric treatment program at the Houston VA Medical Center. The MMPI was administered and a number of demographic variables were collected from patients' archival computerized records. Comparison of MMPI scores indicated that patients without housing had marginally significantly higher scores on the clinical research subscale PD4A (Social Alienation). They were also significantly less likely to be married or employed. Logistic regression analysis indicated that, when multiple predictors were considered, marital status was the only significant risk factor for absence of stable housing. Results underscore the relevance of social services to treatment, discharge, and rehabilitation planning when working with veterans without stable housing.

Some outcome predictors for use in vocational rehabilitation planning

This study examined some predictor variables for positive outcome with a state vocational rehabilitation agency. Referrals to the agency from VA Counseling Psychology were analyzed to develop guidelines for identifying clients with good probability for positive outcome in their vocational rehabilitation planning. All subjects had a history of substance-abuse treatment at the Houston VA Medical Center. Analyses suggested a number of factors are relevant when assessing potential for successful vocational rehabilitation. Provision of drug-free housing, recent work history, and discharge status from a substance-abuse program were identified as relevant factors.

Genetic abnormalities during transition from Helicobacter-pylori-associated gastritis to low-grade MALToma

The helicobacter-associated transition from chronic gastritis to MALToma (lymphoma of mucosa-associated lymphoid tissue) may require genetic change in the host. We have studied gastrectomy specimens from twelve cases of primary B-cell gastric lymphoma showing evidence of chronic gastritis and low-grade or high-grade MALToma to look for allele imbalance at microsatellites for six tumour-suppressor genes. We detected allelic imbalance at two of these loci (DCC in three, APC in two). In two DCC cases allele imbalance was seen in the transition from chronic gastritis to low-grade MALToma and in the third between low-grade and high-grade. Allele imbalance between chronic gastritis and low-grade MALToma is not necessarily causal in the transition. Rather, genetic change has occurred in the process of transformation.

Interleukin 1 receptor antagonist gene polymorphism association with lichen sclerosus

Cytokines play key roles in immune responses, inflammation and fibrosis. The balance between levels of cytokines, their receptors and specific inhibitors controls inflammatory reactions in tissues. The pathogenesis of lichen sclerosus is unknown but probably involves cytokine mediators such as interleukin 1 (IL-1) and interleukin 1 receptor antagonist (IL-1ra). The IL-1ra is a competitive inhibitor of IL-1 alpha and IL-1 beta, and therefore is a powerful endogenous anti-inflammatory molecule. The gene encoding IL-1ra (designated IL-1RN) has a variable number tandem repeat polymorphism in intron 2. There are five alleles of the gene corresponding to 2, 3, 4, 5 and 6 repeats of an 86-bp sequence. We have determined allele frequencies in a control population and a group of 78 patients with lichen sclerosus. The frequency of one of the alleles is related to increasing disease severity. Thus, IL-1RN may be a candidate gene or severity factor for lichen sclerosus or may possibly be a linked marker to another, as yet undefined, gene.

Four new species of Actaeciidae (Isopoda : Oniscidea) from Australia, with a review of the family

Four new species of Actaecia Dana are described from Australia; three of these (A. bipleura, A. cyphotelson and A. nasuta) are from beaches in south-eastem Australia and one (A. forrnida) is from the mid-eastern coast of Queensland. Specimens from Tasmania identified previously as Actaecia pallida Nicholls & Barnes belong to A. bipleura. The same probably applies to others from New South Wales and Lord Howe Island. The distributions of the six Australian species are noted. A review of the monogeneric family Actaeciidae includes a new diagnosis of Actaecia and a key to species. The distributions of the two New Zealand species are listed.

Hidradenitis suppurativa as a presenting feature of premature adrenarche

We report a girl with premature adrenarche, in whom the presenting feature was hidradenitis suppurativa. This association lends support to the view that hidradenitis suppurativa is an androgen-dependent disorder.

Gold induced enterocolitis complicated by cytomegalovirus infection: a previously unrecognised association

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Pain in ambulatory patients with lung or colon cancer. Prevalence, characteristics, and effect

BACKGROUND

Few studies have evaluated the epidemiology and effect of pain in ambulatory patients with cancer who are undergoing active therapy. This information is needed to develop strategies for supportive care in this population.

METHODS

The prevalence and characteristics of pain were determined in a prospective survey of ambulatory patients with lung or colon cancer. To reduce bias and acquire comprehensive information, the methodology used face-to-face interviews by trained quality assurance analysts, a multifaceted assessment instrument, and multivariate statistical analysis.

RESULTS

In a telephone interview, "persistent or frequent" pain during the previous 2 weeks was reported by 57 of 145 (39.3%) patients with lung cancer and 52 of 181 (28.7%) patients with colon cancer; 91 of these patients (47 lung and 44 colon) were interviewed in detail. All patients had excellent performance status, and with the exception of pain location, there were no significant differences between the two tumor types. One-third of the patients had more than one discrete pain. Median pain duration was 4 weeks (range, less than 1 week-468 weeks), and average pain intensity was moderate. Approximately 90% of patients experienced pain more than 25% of the time. Pain interfered moderately or more with general activity and work in approximately half of the patients; more than half reported moderate or greater pain interference in sleep, mood, and enjoyment of life. Multiple regression analysis revealed that the daily frequency of pain, the intensity of the worst pain, the score on a mood scale, and the frequency of the worst pain accounted for 58.7% of the variance in average pain intensity. Likewise, 52.1% of the variance in a derived measure of pain interference in function was explained by the mood score, frequency of the worst pain, number of pains, and pain intensity.

CONCLUSIONS

These data indicate that pain is prevalent among well-functioning ambulatory patients and substantially compromises function in approximately half of the patients who experience it. Pain is a complex symptom; aspects other than intensity, such as frequency, strongly influence its effect.

Identification of a repetitive element in the snail Biomphalaria glabrata: relationship to the reverse transcriptase-encoding sequence in LINE-1 transposons

BamHI-digested Biomphalaria glabrata DNA contains a repetitive 2.0-kb fragment which is readily discernible by ethidium bromide staining. We present evidence that this repetitive element is related at both the nucleotide and amino acid levels to long interspersed nuclear element (LINE)-like transposons. Although comparable elements have been described in several invertebrates, this is the first report of a molluscan homologue. In common with LINE transposons, an open reading frame in the B. glabrata element shows significant homology to reverse transcriptase--a feature believed to allow the dissemination of these elements in the eukaryotic genome.

Value of Emergency Cardiac Enzymes: Audit in a Coronary Care Unit

Medical audit in a district general hospital coronary care unit led to the introduction of an emergency cardiac enzyme service. 91.2% of patients eligible for thrombolysis therapy received treatment following this introduction compared to 73.7% before (P=.05). No patient was treated inappropriately on the basis of a raised cardiac enzyme.

The role of the saphenous nerve in insomnia: a proposed etiology of restless legs syndrome

Entrapment of the saphenous nerve after emergence from its lumbar roots and before its distribution to the medial surface of the leg is suggested as a cause of Restless Legs Syndrome (other anomalies of the saphenous nerve, especially those where the nerve is part of a general neuropathy, are not considered here). This finding is supported by evidence which: 1) identifies Restless Legs Syndrome as a nerve entrapment syndrome from: the dysesthesia in Meralgia Paresthetica, the paraesthesiae of Carpal Tunnel Syndrome and the poorly localized pain in pronator syndrome and suprascapular nerve entrapment; 2) isolates the saphenous nerve as the entrapped nerve from the patient's difficulty in identifying the precise area of sensation in saphenous nerve entrapment at Hunter's Canal; 3) localizes the pelvic region as the site of entrapment from rates of Restless Legs Syndrome of 11 and 19% in pregnant women, a correlation between chronic nonspecific prostatitis and Restless Legs Syndrome.

Egg deposition is the major stimulus for the production of Th2 cytokines in murine schistosomiasis mansoni

To characterize Th cell populations induced by helminth infection, spleen cells from mice infected with Schistosoma mansoni were stimulated with parasite (worm or egg Ag) or mitogen (Con A) and the supernatants assayed for the Th1-specific cytokines IFN-gamma and IL-2 and the Th2-specific cytokines IL-4 and IL-5. Th2 cytokine production was not detected in substantial quantity until the 6 to 8th wk of infection and after reaching peak levels at 8 to 12 wk declined slowly thereafter. The time courses of IL-4 and IL-5 production, whereas differing from each other, closely resembled corresponding published data on IgE and peripheral blood eosinophil levels during murine schistosome infection. In contrast, Th1 cytokine responses occurred only during the first 6 wk of infection and were virtually absent during the peak period of Th2 production. To assess the role of egg deposition in the observed pattern of Th response, cytokine production was assayed in mice carrying unisexual schistosome infections in which parasite eggs are absent. Splenocytes from these animals displayed only marginal Th2 cytokine synthesis but greater Th1 cytokine responses than the corresponding cells from mice with bisexual infections. Moreover, cultures of liver tissue or isolated granulomas from infected mice constitutively produced high levels of IL-4 and IL-5 but failed to synthesize significant amounts of IL-2 and IFN-gamma even when stimulated with egg Ag or mitogen. Taken together the data indicate that egg deposition is the major stimulus of Th2 cytokine response in S. mansoni-infected mice and suggest that T cells belonging to this subset must play a major role in egg granuloma formation.

Egg deposition is the major stimulus for the production of Th2 cytokines in murine schistosomiasis mansoni

To characterize Th cell populations induced by helminth infection, spleen cells from mice infected with Schistosoma mansoni were stimulated with parasite (worm or egg Ag) or mitogen (Con A) and the supernatants assayed for the Th1-specific cytokines IFN-gamma and IL-2 and the Th2-specific cytokines IL-4 and IL-5. Th2 cytokine production was not detected in substantial quantity until the 6 to 8th wk of infection and after reaching peak levels at 8 to 12 wk declined slowly thereafter. The time courses of IL-4 and IL-5 production, whereas differing from each other, closely resembled corresponding published data on IgE and peripheral blood eosinophil levels during murine schistosome infection. In contrast, Th1 cytokine responses occurred only during the first 6 wk of infection and were virtually absent during the peak period of Th2 production. To assess the role of egg deposition in the observed pattern of Th response, cytokine production was assayed in mice carrying unisexual schistosome infections in which parasite eggs are absent. Splenocytes from these animals displayed only marginal Th2 cytokine synthesis but greater Th1 cytokine responses than the corresponding cells from mice with bisexual infections. Moreover, cultures of liver tissue or isolated granulomas from infected mice constitutively produced high levels of IL-4 and IL-5 but failed to synthesize significant amounts of IL-2 and IFN-gamma even when stimulated with egg Ag or mitogen. Taken together the data indicate that egg deposition is the major stimulus of Th2 cytokine response in S. mansoni-infected mice and suggest that T cells belonging to this subset must play a major role in egg granuloma formation.